Question: what is w3c recommendation starts with x
Paraphrase: what is w3c suggestion begins with x
SPARQL (Wikidata): SELECT DISTINCT ?sbj ?sbj_label WHERE { ?sbj wdt:P31 wd:Q2661442 . ?sbj rdfs:label ?sbj_label . FILTER(STRSTARTS(lcase(?sbj_label), 'x')) . FILTER (lang(?sbj_label) = 'en') } LIMIT 25 
Answer: XML Events, XML Events, XPointer, XPointer, XML Encryption, XML Encryption, XInclude, XInclude, XProc, XProc, XHTML+MathML+SVG, XHTML+MathML+SVG, XHTML 1.0 The Extensible HyperText Markup Language (Second Edition), XHTML 1.0 The Extensible HyperText Markup Language (Second Edition), XHTML 1.1 - Module-based XHTML - Second Edition, XHTML 1.1 - Module-based XHTML - Second Edition, XPath and XQuery Functions and Operators 3.1, XPath and XQuery Functions and Operators 3.1, XSLT, XSLT